/*
 * Secure eXtended Message Passing framework
 * Secure eXtended Transport layer implementation: (libsxt)
 * - very similar to SSH2/TLS
 * - using already proven and tested crypto algos
 * - better than TLS for message passing
 *
 * PublicPrivateKeyPairs operation API
 *
 * (c) Alexander Vdolainen 2016 <avdolainen@zoho.com>
 *
 * libsxmp is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * libsxmp is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.";
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>

#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/engine.h>

#include <sxt/errno.h>
#include <sxt/sxtkey.h>

int sxt_key_generate(sxtkey_t *key, int type, int opt)
{
  int r = 0;

  if(!key) return SXT_EINVAL;

  /* set defaults */
  key->type = type;
  key->flags = SXT_PPKP_PRIVATE | SXT_PPKP_PUBLIC;

  switch(type) {
  case PPKP_ED25519:
    key->pubkey = malloc(sizeof(ed25519_pubkey));
    if(!key->pubkey) {
      r = SXT_ENOMEM;
      goto __fall;
    }
    key->privkey = malloc(sizeof(ed25519_privkey));
    if(!key->privkey) {
      r = SXT_ENOMEM;
      goto __safefall0;
    }

    r = crypto_sign_ed25519_keypair(*key->pubkey, *key->privkey);
    if(r) {
      r = SXT_ECRYPTO;
      goto __safefall0;
    }
    break;
  default:
    return SXT_EINVAL;
  }

  if(!r) return SXT_SUCCESS;

 __safefall0:
  if(key->pubkey) free(key->pubkey);
  if(key->privkey) free(key->privkey);

 __fall:
  return r;
}

sxtkey_t *sxt_key_alloc(void)
{
  sxtkey_t *key = malloc(sizeof(sxtkey_t));

  if(!key) return NULL;

  return key;
}

void sxt_key_burn(sxtkey_t *key)
{
  if(!key) return;

  key->priv = NULL;

  switch(key->type) {
  case PPKP_ED25519:
    if(key->pubkey) memset(key->pubkey, 0, sizeof(ed25519_pubkey));
    if(key->privkey) memset(key->privkey, 0, sizeof(ed25519_privkey));
    break;
  default:
    return;
  }

  key->type = 0;
  key->flags = 0;

  return;
}

void sxt_key_free(sxtkey_t *key)
{
  if(!key) return;

  switch(key->type) {
  case PPKP_ED25519:
    if(key->pubkey) free(key->pubkey);
    if(key->privkey) free(key->privkey);
    break;
  default: return; /* cannot free unrecognized key due to the
                    * potential memleak
                    */
  }

  free(key);
  return;
}